Science & Mathematics - 18 September 2007

I have a 12V, 800mA DC Adepter. I want to use it as a variable voltage supplier, then how can a potentiometer be use for varying that 12V? A simple application(connecting output of adepter to fixed terminals of potentiometer as input , any of fixed terminals and terminal of slider as output) doesn’t work for high load application (I > 0.3A) . By doing this sparking appears in potentiometer and it burnout.

2007-09-18 03:10:14 · 1 answers · asked by harsh2035 1 in Engineering

The connection is p-n-n+-n-p. Can it be considered a pnp bipolar junction transistor?

2007-09-18 03:09:42 · 3 answers · asked by duh 2 in Engineering

Is it possable to Evaluate the sqrt of -100?

If so whats the answer?

2007-09-18 03:09:24 · 4 answers · asked by trevor s 2 in Mathematics

a) 2y = 3x + 5
b) y = -x + 7
c) x = 6

2007-09-18 03:04:58 · 1 answers · asked by Anonymous in Mathematics

2007-09-18 03:04:27 · 4 answers · asked by Anonymous in Astronomy & Space

Ideally, I am looking for something that will state:

0 sea level = 100 lbs
1 mile above sea level = X lbs
5 miles above sea level = Y lbs
50 miles = Z
etc.

I'm not overly concerned in the increments or type of measurement (miles, kilometers, pounds, kilograms, etc.) What I am specifically looking for is the ratio at which perceived weight at sea level decreases as distance from the Earth increases.

2007-09-18 03:04:25 · 5 answers · asked by John S 2 in Astronomy & Space

a). x = 3y - 7
b). x - 2y + 3z = 6

2007-09-18 03:03:02 · 2 answers · asked by Anonymous in Mathematics

What makes them initially start to give off heat/light?

2007-09-18 03:01:22 · 7 answers · asked by jay j 2 in Astronomy & Space

2007-09-18 02:56:50 · 2 answers · asked by Anonymous in Engineering

the terms are:

1. isomers
2. isobars
3. isotopes
4. allotropes

2007-09-18 02:51:06 · 4 answers · asked by patel 2 in Chemistry

2007-09-18 02:51:00 · 32 answers · asked by vicky l 2 in Zoology

2007-09-18 02:49:30 · 2 answers · asked by JAMES 4 in Engineering

I was in my earth space science class and this kid says that they heard that scienst belive that they found haven beacuse they found somthing like a black hole onley there is no movement inside i was wondering if someone could givee me more info on this

2007-09-18 02:49:04 · 8 answers · asked by Anonymous in Astronomy & Space

2007-09-18 02:43:06 · 14 answers · asked by TD Euwaite? 6 in Astronomy & Space

The above question is related to electrostatic

2007-09-18 02:36:51 · 7 answers · asked by vivash 1 in Physics

A juggler throws a ball from height of 0.950 m with a vertical velocity of +4.25 m/s and misses it on the way down. What is its velocity when it hits the ground? Show work.

2007-09-18 02:35:48 · 2 answers · asked by Josh S 2 in Physics

What if life on Earth never originated? I believe in the theory of the evolution of molecules into cells which caused life to begin. What if this never happened? Would the Universe just be full of planets and stars and other matter, all of them moving around in the Universe without "aimlessly"?

What if the Big Bang never happened? What if there was no Universe? Would there just be a huge empty space of nothingness?

2007-09-18 02:35:11 · 11 answers · asked by Anonymous in Astronomy & Space

2007-09-18 02:29:01 · 8 answers · asked by Richard C 1 in Mathematics

Someone said to me that wasps are good for nothing, and if we got rid of them nothing in the natural world - as in wasp predators/prey - would miss them. Is this true?

2007-09-18 02:26:29 · 17 answers · asked by ravens.wing 1 in Zoology

1^4 +2^4+3^4+4^4+....+n^4=?
I know for n, n^2 and n^3. Is there any general form for summation upto n^n?

2007-09-18 02:20:05 · 4 answers · asked by Venkateswaran A 2 in Mathematics

If you've read the headline- a meterorite hit in a small village in Peru and people got sick. Someone claims water came out of it. Do you think it was water or something else? Could it be a prelude to an invasion?

2007-09-18 02:19:49 · 14 answers · asked by wisemancumth 5 in Astronomy & Space

What would happen if someone went back in time to BEFORE the big bang?

I mean sure, the Big Bang alledgedly created space and time and such, but in order to create said big bang, wouldn't there have had to be time and space before it to make the explosion?

2007-09-18 02:02:43 · 10 answers · asked by Anonymous in Astronomy & Space

Yesterday I saw not one but two rainbows in the sky. They did not overlap but they seemed to be close.if you know about Venn diagrams, i would say they were like an intersecting set but they did not intersect.To an artist, they may have seemed like a clone or shadow as one was foremost and distinct; the other was in the background. is this just a natural display or is it significant?

2007-09-18 02:02:16 · 4 answers · asked by Aoiffe337 3 in Physics

I feel so sorry for the children. It has become acceptable for kids to use poor grammar and even worse spelling. The kids will grow up to become illiterate adults. They dont even care to try using spell check anymore either. They don't have a chance in the business world. Just how many employees does MacDonalds need, anyway? These questions and answers which are so poorly written are in a science category which should be from and to educated people. How can anyone take you seriously when you cant even spell simple words? Do you really think that you will find the answers to the universe from someone who spells the word 'should' like 'shud'? I think not. I feel so sorry for you people. You won't even understand this until you ask the lady on the other side of the desk at the welfare office.

2007-09-18 02:01:22 · 11 answers · asked by B. 7 in Astronomy & Space

2007-09-18 01:52:54 · 3 answers · asked by physicenovice 1 in Other - Science

I've surfed almost everyday since I can remember and have never understood this.

2007-09-18 01:48:26 · 8 answers · asked by Anonymous in Earth Sciences & Geology

the answers should be in simple & understandable language as the information will be given to the grade 7 students.

2007-09-18 01:46:57 · 4 answers · asked by Anonymous in Weather

Like skipping a stone, except with a bullet. On glass. What angle would you have to shoot it at so that it wouldn't break the glass?

2007-09-18 01:46:52 · 4 answers · asked by mash4t 2 in Physics

just kinda wanted to know....

2007-09-18 01:40:48 · 9 answers · asked by Anonymous in Zoology

integrate x/(x+1) dx

Please show the steps clearly

2007-09-18 01:37:20 · 2 answers · asked by Anonymous in Mathematics